The present invention relates generally to the remote reading of utility meters by electronic means. More particularly, the present invention relates to a method of and a system for remotely reading the utility meters of a user by means of the non-dedicated telephone line connecting the utility user to the central telephone station, in response to a call initiated by equipment at the utility office.
As is common practice, utility companies supply services such as gas, electricity and water to customers who are generally at widely scattered locations. A meter is provided at the customer's location for registering the amount of services or consumption used by the customer. Periodically, usually once per month or every other month, a utility company employee must visit each customer's home or place of business, locate and read the meter, and record the reading. Such readings are utilized to determine the bill to be rendered to the customer. Frequently, in order for the meter reader to gain access to the meter, he must be admitted to the home or place of business where the meter is located, necessitating that the customer or someone else be present sent at the time the meter reader calls. In the absence of the customer or someone to allow the meter reader to gain access, a card is left to be filed in by the customer, or the meter reader must return later to again attempt to read the meter. That presents an inconvenience to the customer and also some peril since, with the constant changing of personnel, the customer cannot know whether it is safe to admit the meter reader, even though he may be wearing the uniform of the utility company.
In addition, a significant labor cost is involved in hiring personnel to read the meters. The task itself is onerous, requiring a great deal of walking on the part of the meter reader, the consumption of a large amount of time per meter read, and a great turnover of personnel. In addition, it is easy for meter readers to make a mistake and, thus, the bill rendered to the customer is inaccurate.
A considerable savings in labor costs can be realized if utility meters are read automatically and the information transmitted to the utility company office using non-dedicated telephone lines. The number of employees engaged in the task of reading meters could thus be substantially reduced. The onerous task of reading the meters would be reduced so that the turnover of personnel could also be decreased. Also, it would not be necessary for customers to be inconvenienced by having to admit a meter reader to the premises and the meters could thus be read on a pre-determined date each month thereby assuring that the reading represents true consumption.
Automatic meter readers are known for use in reading utility meters and for transmitting that reading to the utility company office. However, such apparatus has not been widely accepted because it has involved considerable modification to existing meters, was complex, had a high probable cost of maintenance, and because the apparatus itself and its installation necessitated high costs.
Many of the systems proposed for automatically reading meters from a remote location have involved using existing common non-dedicated, telephone lines as the communications medium for transferring the meter information. Such systems have involved obtaining the information in response to a telephone call initiated by apparatus at the central telephone station. The main advantage of using such non-dedicated telephone lines is that the installation of additional communication lines is unnecessary. The greatest benefit of transferring the meter reading to apparatus at the central station pursuant to a call made by that apparatus is that a complex telephone answering system is not required at the collecting station in order to insure that all incoming calls will be answered in an orderly and efficient manner. Another advantage is that such a system does not involve the use of selectively operable automatic dialing devices at each one of the locations containing the utility meters which are to be read. However, one of the problems with such systems has been the unavoidable ringing of the telephone at the subscriber station pursuant to the call initiated by the apparatus at the central station. In order to avoid that nuisance to the subscriber, a number of different techniques have been suggested.
One such technique involves the use of special telephone company line test circuits which do not activate the bell in the telephone at the subscriber's station for connecting the collecting apparatus at the central station with the subscriber's station. One of the problems of that technique is that it requires the installation of additional equipment at the telephone company's central office. In addition, in order to use such technique, approval from the telephone company must be obtained. A system employing that technique is described in U.S. Pat. No. Re. 26,331, reissued on Jan. 9, 1968, to Brothman, on original U.S. Pat. No. 3,142,726, dated July 28, 1964.
Another technique requires disconnecting the subscriber's telephone from the telephone lines for a certain period of time each day during which time the telephone wires are connected directly to a meter reading device which itself is connected to the utility meters during that time period. In response to an incoming call, the meter reading device transmits the meter data. One problem with this type of scheme is that normal telephone service is completely disrupted for that time period. An additional problem with such an arrangement is that all incoming calls made during that particular time period, including calls made by parties other than the collecting station, will be connected to and answered by the meter reading device. After the meter reading device answers the call, the meter data will be sent out over the telephone lines, without regard to whether the incoming call is from the collecting station. An example of that type of device is disclosed in U.S. Pat. No. 4,126,762, issued on Nov. 21, 1978, to Martin et al.
A similar technique is disclosed in U.S. Pat. No. 4,394,540, issued July 19, 1983 to Willis, et al. The device disclosed therein is a remote meter reader and a method for reading meters over non-dedicated telephone lines in which apparatus present at the telephone subscriber's station responds to interrogation by the central office and transmits meter data thereto over non-dedicated telephone lines.
Each day, the telephone is isolated from the telephone lines for a predetermined data access time. Any call made to the subscriber station during that data access time is answered by the meter reader. In order to determine the source of the call, a coded signal is sent out over the telephone lines by the central office. In the event that the call is from the central office, a coded reply signal is sent back, and the meter reader transmits the data to the central office. If the coded reply signal is not returned, the meter reader generates ringing signals for activating the bell in the subscriber's telephone.
While such a system may overcome some of the disadvantages present in prior art systems, it still retains many of those disadvantages. For example, like earlier prior art devices, the telephone is isolated from the telephone lines for a predetermined data access time each day. Although means have been provided for determining if an incoming call is from the central office, such apparatus requires the use of an on-board microprocessor and other additional complex circuitry. Thus, such an arrangement necessitates increased costs and potential operational failures. In addition, the call from the central office must be closely timed to coincide with the predetermined data access time of each subscriber's station. Otherwise, the meter reader will not be accessible to the central station. Such apparatus is obviously complex and costly.